A method for defining effective pixels in an image sensing array of a light-shading optical touch system is proposed. First, light-shading objects are disposed at three end points of a touch panel, and a shaded image is generated by an image sensing array. Light-shading object pixels corresponding to the light-shading objects are obtained from the shaded image thereafter. Next, the light-shading objects are removed from the touch panel, and a non-shaded image is generated by the image sensing array. Three pixel columns corresponding to the end points are obtained from the non-shaded image, and a pixel with maximum intensity is obtained from each of the three pixel columns. Interpolated pixels between the three brightest pixels are obtained through interpolation from the non-shaded image. Image sensing pixels corresponding to the three brightest pixels and the interpolated pixels in the image sensing array are defined as effective pixels.
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1. A method for defining effective pixels in an image sensing array, adapted to an optical touch system having at least one optical sensing module, a touch panel, and a backlight generator, wherein each of the at least one optical sensing module comprises a light source and an image sensing array, wherein the light source and the image sensing array are disposed at a reference endpoint of the touch panel, wherein the backlight generator is disposed at an edge of the touch panel, wherein the light source provides a sensing light beam, and wherein the method comprises: disposing a light-shading object at each of a first endpoint, a second endpoint, and a third endpoint of the touch panel, and receiving backlight generated by the backlight generator due to the sensing light beam incident thereto by using the image sensing array so as to generate a shaded image, wherein the reference endpoint and the second endpoint are approximately diagonally opposite one another, and wherein the first endpoint and the third endpoint are approximately diagonally opposite one another; obtaining a plurality of light-shading object pixels corresponding to the light-shading objects from the shaded image; removing the light-shading objects from the touch panel, and receiving the backlight generated by the backlight generator by using the image sensing array so as to generate a non-shaded image; obtaining a first pixel column, a second pixel column, and a third pixel column respectively corresponding to the first endpoint, the second endpoint, and the third endpoint from the non-shaded image according to coordinates of the light-shading object pixels; obtaining a first pixel, a second pixel, and a third pixel with maximum intensity respectively from the first pixel column, the second pixel column, and the third pixel column; and obtaining a plurality of first interpolated pixels between the first pixel and the second pixel as well as a plurality of second interpolated pixels between the second pixel and the third pixel through an interpolation method, and defining a plurality of image sensing pixels in the image sensing array corresponding to the first pixel, the second pixel, the third pixel, the first interpolated pixels, and the second interpolated pixels as the effective pixels.
A method for defining effective pixels in an image sensing array of an optical touch system. The system includes a touch panel, a backlight generator at its edge, and an optical sensing module at a reference endpoint, which has a light source and an image sensing array. The light source projects a sensing light beam. The method involves: Placing light-shading objects at three endpoints on the touch panel, including the reference, second, and third endpoints. Capturing a shaded image using the image sensing array from the backlight illuminating the light-shading objects. Identifying light-shading object pixels in the shaded image which correspond to where light-shading objects were located. Removing the objects. Capturing a non-shaded image. Identifying three pixel columns in the non-shaded image corresponding to the three endpoints using coordinates of the light-shading object pixels. Finding the brightest pixel in each of these columns. Using interpolation to find interpolated pixels between the first and second brightest pixels, and also between the second and third brightest pixels. Defines the identified brightest pixels and interpolated pixels as the effective pixels.
2. The method according to claim 1 , wherein before the step of disposing the light-shading object at each of the first endpoint, the second endpoint, and the third endpoint of the touch panel, the method further comprises: receiving the backlight generated by the background generator by using the image sensing array so as to generate a first background image.
This method further improves the effective pixel definition described above. Before positioning the light-shading objects, the image sensing array captures a first background image of the backlight generator. Then places light-shading objects at three endpoints on the touch panel, including the reference, second, and third endpoints. Captures a shaded image using the image sensing array from the backlight illuminating the light-shading objects. Identifying light-shading object pixels in the shaded image which correspond to where light-shading objects were located. Removes the objects. Captures a non-shaded image. Identifies three pixel columns in the non-shaded image corresponding to the three endpoints using coordinates of the light-shading object pixels. Finds the brightest pixel in each of these columns. Uses interpolation to find interpolated pixels between the first and second brightest pixels, and also between the second and third brightest pixels. Defines the identified brightest pixels and interpolated pixels as the effective pixels.
3. The method according to claim 2 , wherein the step of obtaining the light-shading object pixels corresponding to the light-shading objects from the shaded image comprises: for each pixel in the shaded image: comparing whether a difference between intensity of the pixel and intensity of a corresponding pixel in the first background image exceeds a threshold value; and defining the pixel with the difference between the intensity thereof and the intensity of the corresponding pixel in the first background image exceeding the threshold value as one of the shaded pixels.
This method builds on the previous description by using a background image to improve identification of the light-shading object pixels. This is done by comparing each pixel in the shaded image to a corresponding pixel in the first background image generated, according to the method in claim 2. If the intensity difference exceeds a certain threshold, that pixel is then labeled as one of the light-shading object pixels. Then removes the objects. Captures a non-shaded image. Identifies three pixel columns in the non-shaded image corresponding to the three endpoints using coordinates of the light-shading object pixels. Finds the brightest pixel in each of these columns. Uses interpolation to find interpolated pixels between the first and second brightest pixels, and also between the second and third brightest pixels. Defines the identified brightest pixels and interpolated pixels as the effective pixels.
4. The method according to claim 1 , wherein the step of obtaining the first pixel column, the second pixel column, and the third pixel column respectively corresponding to the first endpoint, the second endpoint, and the third endpoint according to the coordinates of the shaded pixels comprises: obtaining a horizontal coordinate of each of the light-shading object pixels; obtaining a plurality of pixel columns with same horizontal coordinates according to the horizontal coordinate of each of the light-shading object pixels; and defining the pixel columns respectively as the first pixel column, the second pixel column, and the third pixel column.
This method details how pixel columns are obtained from the image. After disposing light-shading objects at three endpoints on the touch panel, including the reference, second, and third endpoints. Capturing a shaded image using the image sensing array from the backlight illuminating the light-shading objects. Identifying light-shading object pixels in the shaded image which correspond to where light-shading objects were located (as per claim 1), the horizontal coordinates of the light-shading object pixels are extracted. Pixel columns that share the same horizontal coordinates as the light-shading object pixels are grouped together. These grouped pixel columns are then assigned as the first, second, and third pixel columns, corresponding to the respective endpoints. Removing the objects. Capturing a non-shaded image. Finding the brightest pixel in each of these columns. Uses interpolation to find interpolated pixels between the first and second brightest pixels, and also between the second and third brightest pixels. Defines the identified brightest pixels and interpolated pixels as the effective pixels.
5. The method according to claim 1 , wherein the step of obtaining the first interpolated pixels between the first pixel and the second pixel as well as the second interpolated pixels between the second pixel and the third pixel through the interpolation method comprises: performing linear interpolation computation on coordinates of the first pixel and the second pixel in the non-shaded image so as to obtain the first interpolated pixels; and performing linear interpolation computation on coordinates of the second pixel and the third pixel in the non-shaded image so as to obtain the second interpolated pixels.
This method describes how to find the interpolated pixels. After disposing light-shading objects at three endpoints on the touch panel, including the reference, second, and third endpoints. Capturing a shaded image using the image sensing array from the backlight illuminating the light-shading objects. Identifying light-shading object pixels in the shaded image which correspond to where light-shading objects were located. Removing the objects. Capturing a non-shaded image. Identifying three pixel columns in the non-shaded image corresponding to the three endpoints using coordinates of the light-shading object pixels. Finding the brightest pixel in each of these columns. Linear interpolation is performed using the coordinates of the first and second brightest pixels in the non-shaded image to generate a set of first interpolated pixels. Similarly, linear interpolation is used on the coordinates of the second and third brightest pixels to create a set of second interpolated pixels. Defines the identified brightest pixels and interpolated pixels as the effective pixels.
6. The method according to claim 1 , wherein the backlight generator is a reflective strip, and wherein the image sensing array receives the backlight reflected from the backlight generator due to the sensing light beam incident thereto.
In this implementation, the backlight generator in the optical touch system, used in the method for defining effective pixels described in claim 1, is a reflective strip. The image sensing array receives the backlight reflected from this strip as the sensing light beam strikes it after disposing light-shading objects at three endpoints on the touch panel, including the reference, second, and third endpoints. Capturing a shaded image using the image sensing array from the backlight illuminating the light-shading objects. Identifying light-shading object pixels in the shaded image which correspond to where light-shading objects were located. Removing the objects. Capturing a non-shaded image. Identifying three pixel columns in the non-shaded image corresponding to the three endpoints using coordinates of the light-shading object pixels. Finding the brightest pixel in each of these columns. Uses interpolation to find interpolated pixels between the first and second brightest pixels, and also between the second and third brightest pixels. Defines the identified brightest pixels and interpolated pixels as the effective pixels.
7. The method according to claim 1 , wherein the backlight generator is a light-emitting strip, and wherein the image sensing array receives the backlight guided by the backlight generator due to the sensing light beam incident thereto.
In this implementation, the backlight generator used in the method for defining effective pixels described in claim 1 is a light-emitting strip. The image sensing array receives the backlight guided or emitted by this strip, when the sensing light beam strikes it after disposing light-shading objects at three endpoints on the touch panel, including the reference, second, and third endpoints. Capturing a shaded image using the image sensing array from the backlight illuminating the light-shading objects. Identifying light-shading object pixels in the shaded image which correspond to where light-shading objects were located. Removing the objects. Capturing a non-shaded image. Identifying three pixel columns in the non-shaded image corresponding to the three endpoints using coordinates of the light-shading object pixels. Finding the brightest pixel in each of these columns. Uses interpolation to find interpolated pixels between the first and second brightest pixels, and also between the second and third brightest pixels. Defines the identified brightest pixels and interpolated pixels as the effective pixels.
8. A method for defining effective pixels in an image sensing array, adapted to an optical touch system having at least one optical sensing module and a touch panel, wherein each of the at least one optical sensing module comprises a light source and an image sensing array, wherein the light source and the image sensing array are disposed at a reference endpoint of the touch panel, wherein the light source provides a sensing light beam, and wherein the method comprises: disposing a light-reflecting object at each of a first endpoint, a second endpoint, and a third endpoint of the touch panel, and receiving the sensing light beam reflected back from the light-reflecting objects by using the image sensing array so as to generate a reflected image, wherein the reference endpoint and the second endpoint are approximately diagonally opposite one another, and wherein the first endpoint and the third endpoint are approximately diagonally opposite one another; obtaining a plurality of light-reflecting object pixels corresponding to the light-reflecting objects from the reflected image; obtaining a first pixel column, a second pixel column, and a third pixel column respectively corresponding to the first endpoint, the second endpoint, and the third endpoint from the reflected image according to coordinates of the light-reflecting object pixels; obtaining a first pixel, a second pixel, and a third pixel with maximum intensities respectively from the first pixel column, the second pixel column, and the third pixel column; and obtaining a plurality of first interpolated pixels between the first pixel and the second pixel as well as a plurality of second interpolated pixels between the second pixel and the third pixel through an interpolation method, and defining a plurality of image sensing pixels in the image sensing array corresponding to the first pixel, the second pixel, the third pixel, the first interpolated pixels, and the second interpolated pixels as the effective pixels.
A method for defining effective pixels in an image sensing array of an optical touch system. The system includes a touch panel, and an optical sensing module at a reference endpoint, which has a light source and an image sensing array. The light source projects a sensing light beam. The method involves: Placing light-reflecting objects at three endpoints on the touch panel, including the reference, second, and third endpoints. Capturing a reflected image using the image sensing array, showing the light reflecting off the light-reflecting objects. Identifying light-reflecting object pixels in the reflected image, which correspond to where the objects were located. Identifying three pixel columns in the reflected image corresponding to the three endpoints using coordinates of the light-reflecting object pixels. Finding the brightest pixel in each of these columns. Using interpolation to find interpolated pixels between the first and second brightest pixels, and also between the second and third brightest pixels. Defines the identified brightest pixels and interpolated pixels as the effective pixels.
9. The method according to claim 8 , wherein before the step of disposing the light-reflecting object at each of the first endpoint, the second endpoint, and the third endpoint of the touch panel, the method further comprises: generating a second background image by using the image sensing array.
This method further improves the effective pixel definition in Claim 8. Before positioning the light-reflecting objects, the image sensing array captures a second background image. Then placing light-reflecting objects at three endpoints on the touch panel, including the reference, second, and third endpoints. Capturing a reflected image using the image sensing array, showing the light reflecting off the light-reflecting objects. Identifying light-reflecting object pixels in the reflected image, which correspond to where the objects were located. Identifying three pixel columns in the reflected image corresponding to the three endpoints using coordinates of the light-reflecting object pixels. Finding the brightest pixel in each of these columns. Using interpolation to find interpolated pixels between the first and second brightest pixels, and also between the second and third brightest pixels. Defines the identified brightest pixels and interpolated pixels as the effective pixels.
10. The method according to claim 9 , wherein the step of obtaining the light-reflecting object pixels corresponding to the light-reflecting objects from the reflected image comprises: for each pixel in the reflected image: comparing whether a difference between intensity of the pixel and intensity of a corresponding pixel in the second background image exceeds a threshold value; and defining the pixel with the difference between the intensity thereof and the intensity of the corresponding pixel in the first background image exceeding the threshold value as one of the reflected pixels.
This method builds on the previous description from Claim 9 by using a background image to improve identification of the light-reflecting object pixels. This is done by comparing each pixel in the reflected image to a corresponding pixel in the second background image. If the intensity difference exceeds a certain threshold, that pixel is then labeled as one of the reflected pixels. Then identifying three pixel columns in the reflected image corresponding to the three endpoints using coordinates of the light-reflecting object pixels. Finding the brightest pixel in each of these columns. Using interpolation to find interpolated pixels between the first and second brightest pixels, and also between the second and third brightest pixels. Defines the identified brightest pixels and interpolated pixels as the effective pixels.
11. The method according to claim 10 , wherein the step of obtaining the first pixel column, the second pixel column, and the third pixel column respectively corresponding to the first endpoint, the second endpoint, and the third endpoint from the reflected image according to the coordinates of the light-reflecting object pixels comprises: obtaining a horizontal coordinate of each of the light-reflecting object pixels; obtaining a plurality of pixel columns with same horizontal coordinates according to the horizontal coordinate of each of the light-reflecting object pixels; and defining the pixel columns respectively as the first pixel column, the second pixel column, and the third pixel column.
This method details how pixel columns are obtained from the image from claim 10. After generating a second background image by using the image sensing array. Disposing light-reflecting object at each of a first endpoint, a second endpoint, and a third endpoint of the touch panel, and receiving the sensing light beam reflected back from the light-reflecting objects by using the image sensing array so as to generate a reflected image. Identifying light-reflecting object pixels in the reflected image which correspond to where light-reflecting objects were located, the horizontal coordinates of the light-reflecting object pixels are extracted. Pixel columns that share the same horizontal coordinates as the light-reflecting object pixels are grouped together. These grouped pixel columns are then assigned as the first, second, and third pixel columns, corresponding to the respective endpoints. Finding the brightest pixel in each of these columns. Using interpolation to find interpolated pixels between the first and second brightest pixels, and also between the second and third brightest pixels. Defines the identified brightest pixels and interpolated pixels as the effective pixels.
12. The method according to claim 10 , wherein the step of obtaining the first interpolated pixels between the first pixel and the second pixel as well as the second interpolated pixels between the second pixel and the third pixel through the interpolation method comprises: performing linear interpolation computation on coordinates of the first pixel and the second pixel in the reflected image so as to obtain the first interpolated pixels; and performing linear interpolation computation on coordinates of the second pixel and the third pixel in the reflected image so as to obtain the second interpolated pixels.
This method describes how to find the interpolated pixels from claim 10. After generating a second background image by using the image sensing array. Disposing light-reflecting object at each of a first endpoint, a second endpoint, and a third endpoint of the touch panel, and receiving the sensing light beam reflected back from the light-reflecting objects by using the image sensing array so as to generate a reflected image. Identifying light-reflecting object pixels in the reflected image which correspond to where light-reflecting objects were located, Identifying three pixel columns in the reflected image corresponding to the three endpoints using coordinates of the light-reflecting object pixels. Finding the brightest pixel in each of these columns. Linear interpolation is performed using the coordinates of the first and second brightest pixels in the reflected image to generate a set of first interpolated pixels. Similarly, linear interpolation is used on the coordinates of the second and third brightest pixels to create a set of second interpolated pixels. Defines the identified brightest pixels and interpolated pixels as the effective pixels.
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April 14, 2015
August 8, 2017
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